1. Field of the Invention
The present invention relates to a data storage method and data storage device for storing the pattern data of the photomask, such as the mask and the reticle, created in the semiconductor-device manufacturing processes.
2. Description of the Related Art
In recent years, as for the semiconductor-device manufacturing processes, such as the LSI manufacturing processes, the amount of data of the patterns, such as the photomask, is increasing with the use of smaller semiconductor devices.
Moreover, the graphic pattern compensation processing using the optical proximity correction (OPC) method etc. has become indispensable with the use of smaller graphic patterns, and this also makes the amount of data of the patterns increase further.
The photomask is a component through which a photosensitive film, deposited on the wafer, will then be exposed, in order to form the electronic circuit pattern for each layer of the IC. The photomask is commonly used in the photolithographic method for the semiconductor-device manufacturing processes when it is needed to transfer the circuit pattern to the wafer surface.
There are various kinds of the photomask created in the semiconductor-device manufacturing processes. The photomask may be roughly classified into the mask and the reticle. The mask is used wherein the circuit patterns each having the size equivalent to the size of the semiconductor device are formed on the photomask and they are transferred to the wafer surface by one operation. The reticle is used with the reduction projection exposure device (stepper).
Generally, both the former and the latter are collectively referred to as the photomask. In recent years, with the use of smaller semiconductor devices, the main current of the photomask which is more frequently used in the photolithographic method is the reticle.
In the conventional pattern data for the LSI manufacturing processes, the black and white pattern images are determined in accordance with the resist.
Moreover, there is the tendency in which the amount of data of the patterns, such as the photomask, increases with the complication of pattern form.
In addition, Japanese Laid-Open Patent Application No. 06-151286 discloses the method of exposure for the proximity effect correction in the electron beam exposure in which the multiple exposure is not used for the compensation exposure when the Ghost method is used.
Moreover, Japanese Laid-Open Patent Application No. 06-029199 discloses the method of creation of the inverted mask pattern data for preparing the photomask by exposing the resist to the beam exposure.
As mentioned above, as for the semiconductor-device manufacturing processes, such as the LSI manufacturing processes, the amount of data of the patterns, such as the photomask, is increasing with the use of smaller semiconductor devices.
According to the conventional data storage method, making determination as to whether the black pattern image or the white pattern image is selected for the pattern data storage is a fixed selection in accordance with the resist. Namely, when the pattern data are divided into a plurality of fields (which are the fixed regions preset in the data for exposure/inspection and hereinafter called the fields) and each pattern for every field is stored, the pattern of the fixed white or black image is stored for every field.
For example, when the pattern data of the white images are stored in accordance with the resist, the pattern of the white image is stored respectively for each field. On the contrary, when the pattern data of the black images are stored in accordance with the resist, the pattern of the black image is stored respectively for each field.
However, with the complication of pattern form, the number of the patterns to be stored in the white image for each field may be increased more than that in the case where they should be stored in the black image.
In this case, according to the conventional data storage method, the amount of the pattern data actually stored is beyond the necessary amount, and the problem arises in that the amount of the pattern data stored is unnecessarily increased.
It is conceivable that, in the near future, the countermeasure for the handling of large-scale data, the data transmission, or the data storage must be taken by the arrangement of the device environment or the like. It is expected that the costs, such as the plant-and-equipment investment, are increased for the arrangement of the device environment. Therefore, it is demanded that the costs needed for the arrangement of the device environment be reduced as much as possible.